Dear experts

Im trying to communicate with modbus Emerson CNG050 device through cp 340, here are some details of what I want and what I did:

 I want to read 7 real values from the device that starting at address 247 and because it is Floating-point register pairs then it continue to 262 which mean that I have to read 14 registers. 

the device address is 1

reading command is 4

start reading address is 247 dec as F7 as hex

number of registers is 14 dec ,  E hex

and the LRC is F6

all these are in the modbus send DB, 

I also have receive DB. 

I checked the device with my PC and it working fine with the setting that I put in the HW configuration. put I could not get it to work with siemens PLC.  I send the request but I dont get any answer 

I attached the project here. please see it and help me to see what Im doing wrong.

I forget to mention that I use 2 wires RS 485

kind regards

Ebrahem

hello Smiffy

thank you for the very useful answer, I used the TIBI68 after your answer and it work fine. I still have 2 questions. 

1- Is there same functions for TIA V13?

2- how to convert 4 bytes to real value?

Kind regards

Ebrahem

Thank you Smiffy 

I managed to convert 4 bytes to real value by using tags overlapping method which described here. I also attached a screenshot of my FC.

Kind Regards

Ebrahem